Background: The aim of this study was to evaluate the benefits from the addition of induction chemotherapy (IC) to concurrent chemoradiotherapy (CCRT) in N2-3 nasopharyngeal carcinoma (NPC).
Methods: A total of 3089 patients with nonmetastatic NPC, staged as N2-3 were retrospectively reviewed. IC contained cisplatin (80 mg/m2) with 5-fluorouracil (800 mg/m2/day over 120 h), or cisplatin (80 mg/m2) with docetaxel (80 mg/m2), or cisplatin (60 mg/m2) with 5-fluorouracil (600 mg/m2 over 120 h), and docetaxel (60 mg/m2) administered at 3-week intervals for two or three cycles. Concurrent chemotherapy consisted of cisplatin (80 or 100 mg/m2) given in weeks 1, 4, and 7 of radiotherapy, or cisplatin (40 mg/m2) given weekly during radiotherapy. Overall, three well-matched risk groups (low, intermediate, and high risk) were created using propensity score matching, and IC plus CCRT was compared with CCRT in each risk group. Our primary endpoint was distant metastasis-free survival (DMFS).
Results: A nomogram for DMFS was established with good prognostic accuracy (C-index, 0.69; 95% confidence interval, 0.64-0.73). The survival curves for low, intermediate, and high-risk groups stratified by the nomogram were significantly different between all three risk groups, with corresponding 5-year DMFS rates of 90.7%, 79.4%, and 64.9%, respectively (p < 0.001). IC plus CCRT was significantly associated with superior DMFS as compared with CCRT alone (69.5% versus 56.7%, p = 0.004) in the high-risk group. However, no significant difference between IC plus CCRT and CCRT was observed (p = 0.831 and 0.608, respectively) in the intermediate and low-risk groups.
Conclusions: Our findings can help accurately guide the treatment of individual patients with advanced N-stage NPC.
Keywords: advanced N-stage; benefit; induction chemotherapy; nasopharyngeal carcinoma; nomogram; propensity score matching method.